how to add a component to a gameobject in unity script code example

Example 1: c# addcomponent

// Consider an existing GameObject, gameObj
Rigidbody addedComp = gameObj.AddComponent<Rigidbody>() as Rigidbody;
// You can also add custom components by class name

Example 2: On add component unity

void Reset()
{
  //Your code here
}